"Normally it's the other way around, wholesale price weakness leads consumer price weakness," Low said. "The unusual reversal suggests this year's bout of disinflation is demand driven, reflecting consumers' reticence to spend after last year's sharp slowdown in wage and salary income and decline in savings."

On Friday, the Labor Department is scheduled to release its more closely watched report on consumer prices in the month of July. Consumer prices are expected to rise by 0.2 percent.